Electrical steering drives have a steering motor, the input signal of which depends on the recorded position of the steering transmitter (drawbar or steering wheel). A steering drive, which gears down the steering motor tuning at a higher speed, is required in order to transfer the rotary motion of the steering motor to a steering plate, through which the driven wheel is swivel mounted around a vertical axis. In order to record the steering angle, a rotation angle sensor is provided, the output signal of which goes to the steering control.
Different options are known to record the actual angle of the steered wheel with the help of a sensor. A sensor drive, which is coupled with the shaft of the steering motor, is provided in a known embodiment. When the steering motor moves the steering plate with a plurality of revolutions (e.g. 100 revolutions) in a working range of e.g. ±90° via the steering drive, the sensor moves in its measurement range of e.g. ±180°. The sensor is hereby arranged on the side of the steering motor that is opposite the steering drive, which accommodates the available cramped installation space. However, the disadvantage is that a complicated sensor drive must be provided.
Furthermore, it is known to drive the sensor drive with the shaft of an intermediate stage in the steering drive. Here also, the transmission of the sensor drive should be selected such that the sensor is moved in its measurement range if the steering plate moves in its working range. The transmission of the sensor drive is naturally smaller than in the case of the embodiment described above. On the other hand, the disadvantage is that the rotation angle sensor is arranged on the drive side of the motor. The drive of a sensor via a spur wheel stage directly on the steering plate leads to a structure that takes up a lot of space, since the steering plate naturally has a large diameter.
Finally, it is also known to record the actual angle on the steering plate and/or on the steering motor via an impulse transmitter. However, only a relative measuring is thereby obtained, whereby a referencing run is required each time the steering drive is started.
The object of the invention is to create a steering drive for a wheel of a ground conveyor with an apparatus for recording the actual angle of the steered wheel, which gets by with a very simple sensor drive.